BALTIMORE — Fans watching NFL games on television have grown accustomed to the imaginary yellow line that runs across the field in accord with the first-down marker.

That first-down line could one day become part of the in-game experience at all 32 NFL stadiums.

Alan Amron, with financial backing from former NFL player and broadcaster Pat Summerall, has developed the First Down Laser System. Amron said the system projects a first-down line across the field that can be seen in the stadium and on TV.

The league is intrigued, but not completely sold on the idea — not yet anyway.

“The NFL is our prime customer at this point,” Amron said, “and if we can make something that they like, maybe the NCAA and Canadian Football League will follow suit.”

Amron first met with the NFL in 2003 and again in 2009. There may soon be future meetings.

“They give me different opinions and suggestions along the way,” Amron said. “We comply with them and come back. They tell me it took them years and years to implement replay and the overhead cam. The NFL right now has made it very clear to us that they didn’t want to eliminate the chains, but augmenting them wouldn’t be a bad idea.”

League spokesman Greg Aiello said, “We have not been convinced that it would work for us, but we are open to further discussion after the season.”

The laser system would be attached to the first-down markers on both sides and project a contrasting light green line across the field. The system would work in accord with the chain gang, but is designed to provide a more accurate focal point in terms of measurements. When a player hits the turf, by theory, it would become immediately apparent whether he made a first down.

“A misplaced ball on a first-down measurement can mean the difference between winning and losing a game,” Summerall said.

For fans at home, the first-down line is a visual aid that has become as much a part of the telecast as replay and out-of-town highlights. Amron got the idea for the laser after watching a game at home, then going to the stadium and having to do without the line across the field.

“Right away I realized it would be a great thing to be able to project it onto the field,” he said. “I filed patents on it within weeks.”

In recent years, the NFL has attempted to lure fans from home by making larger replay screens, displaying in-house photos of what the replay official is watching and showing clips from games around the league. Could a first-down line be the next addition?

“It will help all teams bring more fans to the stadium to see the game in person,” Summerall said.